Bookmarks have typically provided a method for marking a page in a book and/or holding a book open to a particular location. Differences in the size of books and the types of materials used in construction (hardback versus paperback, thin versus thick, heavy paper versus light paper, etc.) present a problem in finding one bookmark that is suitable for use with most types of books.
Some bookmarks, such as U.S. Pat. No. 704,410, issued July 8, 1902, to C. P. Weaver, and U.S. Pat. No. 1,438,299, issued Dec. 12, 1922, to M. J. Conter, are suitable for use with a hardback book but are not usable with paperback books. Other bookmarks, such as U.S. Pat. No. 840,475, issued Jan. 8, 1907, to M. J. Conter, may be suitable for pages made from a heavyweight paper, but would be unsuitable for use with a lightweight paper. In addition, bookmarks have been made with special widening procedures to accommodate books of varying book thicknesses, such as U.S. Pat. No. 1,700,846, issued Feb. 5, 1929, to B. Klein, and U.S. Pat. No. 2,436,609, issued Aug. 16, 1946, to A. Safier. A need thus exists for a bookmark that automatically marks the page in a book as each page is turned and that is suitable for use with books of varying size and materials of construction.